diff -urN fix_76231_v2/fix_76231.sh fix_76231_v3/fix_76231.sh
--- fix_76231_v2/fix_76231.sh	2016-05-24 08:43:54.000000000 +0200
+++ fix_76231_v3/fix_76231.sh	2016-05-24 11:23:16.000000000 +0200
@@ -25,6 +25,29 @@
 	ROOTPATH="${1}"
 fi

+_check_required_commands() {
+    local missed=""
+
+    until [ -z "$1" ]; do
+        type -t $1 >/dev/null 2>/dev/null
+        if [ $? -ne 0 ]; then
+            missed="$missed $1"
+        fi
+        shift
+    done
+
+    echo $missed
+}
+
+REQUIRED_COMMANDS='patch'
+MISSED_REQUIRED_COMMANDS=$(_check_required_commands $REQUIRED_COMMANDS)
+if [ ! -z "${MISSED_REQUIRED_COMMANDS}" ]
+then
+    echo "Error! Some required system tools, that are utilized in this script, are not installed:" >&2
+    echo "Tools \"${MISSED_REQUIRED_COMMANDS}\" are missed, please install them." >&2
+    exit 1
+fi
+
 find -L "${ROOTPATH}" -type f -name "SystemEnvironmentBuilder.php" -print -o -type f -name "config_default.php" -print 2>/dev/null | while read FILE; do
 	line=$(grep -oE "define\('TYPO3_branch', '[0-9.]+" "${FILE}" 2>/dev/null)
 	if [ -z "${line}" ]; then